Engaging assembly and slide rail mechanism, drawer and refrigerator having the same

ABSTRACT

An engagement assembly, a drawer, and a refrigerator having same. The engagement assembly comprises a first engagement part matching the drawer and a second engagement part matching a refrigerator body; one of the first and second engagement parts is a gear, and the other one is a rack; the rack has a tooth surface that allows the gear to travel; the rack comprises a main rack and an extension rack; when the drawer is in a closed state, the tooth surface has a first stroke length; when the drawer is in an opening process, the extension rack moves to a travel path of the gear so that the tooth surface has a second stroke length; when the drawer is in a closing process, the extension rack is reset the first stroke length is smaller than the second stroke length. The length of the tooth surface increases in the opening process.

The present application is a 35 U.S.C. § 371 National Phase conversion of International (PCT) Patent Application No. PCT/CN2018/122073, filed on Dec. 19, 2018, which claims priority to Chinese Patent Application No. 201810380307.7, filed to the Chinese Patent Office on Apr. 25, 2018 and titled “Engaging assembly and Slide Rail Mechanism, Drawer and Refrigerator Having the Same”, the content of which is incorporated herein by reference in its entirety. The PCT International Patent Application was filed and published in Chinese.

TECHNICAL FIELD

The present invention relates to the field of household appliances and particularly to an engaging assembly and a slide rail mechanism, a drawer and a refrigerator having the same.

BACKGROUND

Currently, refrigerators are requisite household appliances in people's daily life. The refrigerator is usually provided with a drawer in which articles to be refrigerated may be placed and stored.

In the prior art, an opening or closing process of the drawer is usually implemented through a slide rail, which facilitates a user to place or remove foods into or from the drawer. However, due to the limitation of a sliding path of the slide rail, the distance through the drawer may be pulled out is also limited, which does not facilitate the user to place or remove foods into or from the drawer.

SUMMARY

An object of the present invention is to provide an engaging assembly and a slide rail mechanism, a drawer and a refrigerator having the same.

To achieve one of the above objects of the present invention, an embodiment of the present invention provides an engaging assembly for assisting in opening or closing a drawer. The engaging assembly comprises a first engaging portion that engages with a drawer and a second engaging portion that engages with a cabinet, one of the first engaging portion and the second engaging portion is a gear, and the other is a rack, the rack has a tooth surface enabling the gear to travel, and the rack comprises a main rack and an extension rack; when the drawer is in a closed state, the tooth surface has a first travel length; when the drawer is in an opening process, the extension rack moves onto a travel path of the gear so that the tooth surface has a second travel length; when the drawer is in a closing process, the extension rack returns, and the first travel length is shorter than the second travel length.

As a further improvement of an embodiment of the present invention, the first engaging portion is a gear, and the second engaging portion is a rack.

As a further improvement of an embodiment of the present invention, the main rack comprises a first end portion and a second end portion which are arranged opposite to each other, a direction from the first end portion to the second end portion is the direction in which the drawer is opened; when the drawer is in an open state, the extension rack protrudes beyond the second end portion in a direction away from the first end portion.

As a further improvement of an embodiment of the present invention, the main rack has a main tooth surface, and the extension rack has an extension tooth surface; when the drawer is in the open state, the extension tooth surface and the main tooth surface are spliced into a continuous tooth surface.

As a further improvement of an embodiment of the present invention, the engaging assembly further comprises a driving member; when the drawer is in an opening process, the driving member drives the extension rack to move onto a travel path of the gear; when the drawer is in the closing process, the driving member drives the extension rack to return.

As a further improvement of an embodiment of the present invention, the extension rack is movably connected to the main rack.

As a further improvement of an embodiment of the present invention, the main rack comprises a first end portion and a second end portion which are arranged opposite to each other, the direction from the first end portion to the second end portion is the direction in which the drawer is opened, the extension rack is pivotally connected to the second end portion; when the drawer is in the opening process, the extension rack rotates relative to the second end portion and protrudes beyond the second end portion in a direction away from the first end portion.

As a further improvement of an embodiment of the present invention, the main rack has a main tooth surface, and the extension rack has an extension tooth surface; when the drawer is in the opening process, the extension rack rotates relative to the second end portion so that the extension tooth surface and the main tooth surface are spliced into a continuous tooth surface.

As a further improvement of an embodiment of the present invention, when the drawer is in the closed state, an angle between the extension rack and the main rack is in a range of 30° to 120°.

As a further improvement of an embodiment of the present invention, the engaging assembly further comprises a driving member, and the extension rack has an adapting portion that engages with the driving member; when the drawer is in the opening process, the driving member acts on the adapting portion to cause the extension rack to rotate in a direction away from the second end portion; when the drawer is in the closing process, the driving member disengages from the adapting portion to cause the extension rack to rotate in a direction close to the second end portion.

As a further improvement of an embodiment of the present invention, a return torsion spring is provided at a connection of the extension rack and the main rack.

As a further improvement of an embodiment of the present invention, a limiting portion is disposed at the second end portion of the main rack; when the extension rack rotates in a direction adjacent to the second end portion and contacts the limiting portion, the limiting portion restricts the extension rack from continuing to rotate in the direction adjacent to the second end portion.

As a further improvement of an embodiment of the present invention, the limiting portion comprises limiting teeth, and when the drawer is in the closed state, the limiting teeth and the extension rack engage with each other.

As a further improvement of an embodiment of the present invention, the limiting portion comprises a limiting surface located on a rotation path of the extension rack, an adapting surface is provided on a side of the extension rack, and when the drawer is in the closed state, the limiting surface and the adapting surface interfere with each other.

As a further improvement of an embodiment of the present invention, the main rack comprises a first end portion and a second end portion which are arranged opposite to each other, the direction from the first end portion to the second end portion is the direction in which the drawer is opened, a receiving space is disposed in a region adjacent to the second end portion, and the extension rack is movably disposed in the receiving space; when the drawer is in the opening process, the extension rack moves in the receiving space so that the extension rack protrudes beyond the second end portion in a direction away from the first end portion.

As a further improvement of an embodiment of the present invention, the main rack has a main tooth surface, the extension rack has an extension tooth surface, and when the drawer is in the opening process, the extension rack moves in the receiving space so that the extension tooth surface and the main tooth surface are spliced into a continuous tooth surface.

As a further improvement of an embodiment of the present invention, the receiving space comprises a bottom portion away from the main tooth surface and a top portion adjacent to the main tooth surface; when the drawer is in the closed state, the extension rack is located between the bottom portion and the top portion; when the drawer is in the opening process, the extension rack moves close to the top portion so that the extension tooth surface and the main tooth surface are spliced into a continuous tooth surface.

As a further improvement of an embodiment of the present invention, the main tooth surface comprises a rear main tooth surface located in an intermediate region between the top portion and the first end portion, and a front main tooth surface located at the top portion, and the rear main tooth surface is continuous with the front main tooth surface.

As a further improvement of an embodiment of the present invention, the engaging assembly further comprises a driving member, and the extension rack has an adapting portion that engages with the driving member; when the drawer is in a closed state, the driving member abuts against the adapting portion so that the extension rack is located between the bottom portion and the top portion; when the drawer is in the opening process, the driving member disengages from the adapting portion to cause the extension rack to move close to the top portion; when the drawer is in the closing process, the driving member abuts against the adapting portion so that the extension rack moves close to the bottom portion.

As a further improvement of an embodiment of the present invention, an elastic member is provided between the extension rack and the bottom portion, and when the driving member disengages from the adapting portion, the elastic member drives the extension rack to move close to the top portion.

As a further improvement of an embodiment of the present invention, the receiving space has a side wall connecting the bottom portion with the top portion, the side wall is provided with at least one travel slot, and the extension rack is provided with a projection mating with the travel slot; when the driving member disengages from the adapting portion, the projection slides in the travel slot to drive the extension rack to move closer to the top portion.

As a further improvement of an embodiment of the present invention, an angle in a direction away from the first end portion is provided between the travel slot and the bottom portion, and the angle is an acute angle.

As a further improvement of an embodiment of the present invention, the receiving space has two side walls disposed opposite each other, and each side wall has two travel slots distributed in parallel.

As a further improvement of an embodiment of the present invention, the extension rack and the receiving space cooperate with each other so that the extension tooth surface and the main tooth surface are always at the same height; when the drawer is in the opening process, the extension rack moves in a direction away from the first end portion so that the extension tooth surface and the main tooth surface are spliced into a continuous tooth surface.

As a further improvement of an embodiment of the present invention, the main tooth surface comprises a rear main tooth surface adjacent to the first end portion and a front main tooth surface adjacent to the second end portion, and the rear main tooth surface is continuous with the front main tooth surface; when the drawer is in a closed state, the extension tooth surface is disposed adjacent to the front main tooth surface; when the drawer is in the opening process, the extension tooth surface moves in a direction away from the front main tooth surface; when the drawer is in the closing process, the extension tooth surface moves in a direction close to the front main tooth surface.

As a further improvement of an embodiment of the present invention, the engaging assembly further comprises a driving member connected to the extension rack; when the drawer is in the opening process, the driving member drives the extension rack to move in a direction away from the first end portion; when the drawer is in the closing process, the driving member drives the extension rack to move in a direction close to the first end portion.

As a further improvement of an embodiment of the present invention, the driving member comprises a link, a slider and a driving block, and the link is used to connect the extension rack with the slider; when the drawer is in the closed state, the driving block and the slider engage with each other; when the drawer is in the opening process, the driving block drives the extension rack to move in a direction away from the first end portion via the slider and the link; when the drawer is in the closing process, the driving block drives the extension rack to move in a direction close to the first end portion via the slider and the link.

As a further improvement of an embodiment of the present invention, an accommodating slot for accommodating the driving member and the extension rack is provided in the receiving space, the accommodating slot comprises two side walls disposed opposite each other, each side wall is provided with a first slot for limiting a moving direction of the slider, the first slot comprises a first section adjacent to the first end portion and a second section adjacent to the second end portion, the second section is away from the main tooth surface relative to the first section, and the slider is movably connected to the link; when the drawer is in the opening process, the driving block drives the slider to travel from the first section to the second section, and then the slider rotates relative to the link so that the driving block disengage from the slider; when the drawer is in the closing process, the driving block engages with the slider and drives the slider to travel from the second section to the first section.

As a further improvement of an embodiment of the present invention, the slider is provided with a notch that engages with the driving block, and the driving member further comprises a return spring connected to the slider; when the drawer is in the opening process and the slider enters the second section, the slider rotates in a direction away from the first end portion, and one side of the notch is inclined so that the driving block disengages from the notch; when the drawer is in the closing process, the driving block enters the notch from the inclined side of the notch, and the return spring drives the slider to rotate in a direction close to the first end portion so that the driving block and the notch engage with each other, and the return spring drives, via the slider, the driving block, the link and the extension rack to move together toward the first end portion.

As a further improvement of an embodiment of the present invention, a post is provided at a connection of the slider and the link, the side wall further has a second slot for restricting the moving direction of the extension rack and a third slot for restricting the moving direction of the post, and a length of the second slot is equal to a length of the third slot.

In order to achieve one of the above-mentioned objects of the invention, an embodiment of the present invention provides a slide rail mechanism, which comprises the engaging assembly according to any one of the above technical solutions and a slide rail assembly that fits with the engaging assembly.

As a further improvement of an embodiment of the present invention, the slide rail assembly has an upper rail, a middle rail and a lower rail that are slidingly fitted to each other, the lower rail is connected to the cabinet, the middle rail is movably connected to the upper rail and the lower rail, the upper rail is connected to the drawer, the gear is connected to the upper rail, and the rack is connected to the cabinet and/or the lower rail.

As a further improvement of an embodiment of the present invention, the slide rail mechanism comprises two slide rail assemblies and two engaging assemblies located on opposite sides of the drawer, and the two gears are connected by a link.

In order to achieve one of the above-mentioned objects of the present invention, an embodiment of the present invention provides a drawer comprising the slide rail mechanism as described above.

In order to achieve one of the foregoing objectives of the present invention, an embodiment of the present invention provides a refrigerator comprising the drawer as described above.

Compared with the prior art, the present invention has the following advantageous effects: the length of the tooth surface of the rack according to an embodiment of the present invention is variable and becomes larger in the opening process of the drawer, so that the pull-out distance of the drawer becomes larger, which facilitates the user to have access to articles in the drawer and improves the user experience; in addition, the length of the tooth surface increases only in the opening process of the drawer, the length of the tooth surface is small when the drawer is in the closed state, and the existence of extension racks does not hinder the normal opening or closing process of the drawer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a closed state of a drawer according to an embodiment of the present invention;

FIG. 2 is an exploded view of FIG. 1;

FIG. 3 is a schematic view of a closed state of a slide rail mechanism according to an embodiment of the present invention;

FIG. 4 is an exploded view of a partial portion of FIG. 3;

FIG. 5 is a schematic view of an open state of a drawer according to an embodiment of the present invention;

FIG. 6 is a schematic view of an open state of a slide rail mechanism according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a closed state of a drawer according to a first embodiment of the present invention;

FIG. 8 is an exploded view of FIG. 7;

FIG. 9 is a schematic diagram of the cooperation of a main rack and an extension rack according to a first embodiment of the present invention;

FIG. 10 is an exploded view of FIG. 9;

FIG. 11 is a schematic diagram of the cooperation of the main rack and the extension rack according to the first embodiment of the present invention as viewed from another angle of view;

FIG. 12 is a schematic view of an open state of the drawer according to the first embodiment of the present invention;

FIG. 13 is a schematic diagram of a gear and a rack according to another embodiment;

FIG. 14 is a schematic diagram of a closed state of a drawer according to a second embodiment of the present invention;

FIG. 15 is an exploded view of FIG. 14;

FIG. 16 is a schematic view of an open state of the drawer according to the second embodiment of the present invention;

FIG. 17 is a schematic diagram of the cooperation of the main rack and the extension rack in the open state according to the second embodiment of the present invention;

FIG. 18 through FIG. 21 are schematic diagrams of the cooperation of the main rack and the extension rack in other embodiments;

FIG. 22 is a schematic diagram of a closed state of a drawer according to a third embodiment of the present invention;

FIG. 23 is a schematic diagram of a main rack region according to a third embodiment of the present invention;

FIG. 24 is an exploded view of FIG. 22;

FIG. 25 is a schematic diagram with the main rack omitted in the third embodiment of the present invention;

FIG. 26 is an exploded view of FIG. 25;

FIG. 27 is a schematic diagram of the cooperation of the extension rack and a driving member according to the third embodiment of the present invention;

FIG. 28 is a schematic diagram of an open state of a drawer according to the third embodiment of the present invention;

FIG. 29 is a schematic diagram of a drawer return process according to the third embodiment of the present invention.

DETAILED DESCRIPTION

The present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention. Structural, methodological or functional variations made by those skilled in the art based on these embodiments are all included in the protection scope of the present invention.

In the figures of the present application, some dimensions of the structures or parts may be exaggerated relative to other structures or parts for convenience of illustration, and therefore they are only used to illustrate basic structures of the subject matter of the present application.

In addition, the terms “left”, “right”, “left side”, “right side”, and the like as used here, which denote spatial relative positions, describe the relationship of a unit or feature relative to another unit or feature in the accompanying drawings for the purpose of illustration. The terms of the spatial relative positions may be intended to include different orientations of the device in use or operation other than the orientations shown in the accompanying drawings. For example, the units that are described as being located on the “below” or “beneath” other units or features will be located “above” other units or features if the device in the accompanying drawings is turned upside down. Thus, the exemplary term “below” can encompass both the orientations of above and below. The device may be otherwise oriented (rotated by 90 degrees or facing other directions) and the space-related descriptors used here are interpreted accordingly.

An embodiment of the present invention provides a refrigerator (not shown). The specific structure of the refrigerator may be found from depictions of refrigerators in the prior art and will not be detailed any more here.

With reference to FIG. 1 and FIG. 2, a drawer 400 is provided in a refrigerator cabinet 500, and the drawer 400 can be opened or closed relative to the cabinet 500.

The drawer 400 includes a drawer body 401 and a drawer door body 402 connected to the drawer body 401. The drawer body 401 is driven into and out of the cabinet 500 by acting on the drawer door body 402.

The drawer 400 further includes a slide rail mechanism 300. The slide rail mechanism 300 is disposed between the drawer 400 and the cabinet 500. The slide rail mechanism 300 is used to assist in opening or closing the drawer 400 relative to the cabinet 500.

The slide rail mechanism 300 includes an engaging assembly 100 and a slide rail assembly 200 that engage with each other.

In the present embodiment, with reference to FIG. 3 and FIG. 4, the slide rail mechanism 300 includes two slide rail assemblies 200 and two engaging assemblies 100 located on opposite sides of the drawer 400, but is not limited thereto.

Here, the two engaging assemblies 100 (and the two sliding assemblies 200) are located on the left and right sides of the drawer 400, respectively, but the distribution thereof are not limited thereto. The two engaging assemblies 100 (and the two sliding assemblies 200) may also be distributed in other forms.

The slide rail assembly 200 has an upper rail 201, a middle rail 202 and a lower rail 203 that are slidably fitted to each other. The lower rail 203 is connected to the cabinet 500, the middle rail 202 is movably connected to the upper rail 201 and the lower rail 203, and the upper rail 201 is connected to the drawer 400.

In use, the lower rail 203 is fixed, and the middle rail 202 and the upper rail 201 are openable and closeable relative to the lower rail 203, thereby driving the drawer 400 to be opened or closed in the cabinet 500, that is, the lower rail 203 is a fixed rail, and the middle rail 202 and the upper rail 201 are moveable rails.

The engaging assembly 100 is used to assist in opening or closing the drawer 400.

The engaging assembly 100 includes a first engaging portion 10 that engages with the drawer 400 and a second engaging portion 20 that engages with the cabinet 500.

The first engaging portion 10 is disposed at the upper rail 201.

Here, a bracket 204 is further connected to a side of the upper rail 201 away from the lower rail 203, the upper rail 201 and the bracket 204 are fixed to each other, and the first engaging portion 10 substantially engages with the bracket 204.

A connecting sheet 403 is further provided between both ends of the drawer door body 402 and the two brackets 204.

Here, the connecting sheet 403 is fixed to the bracket 204 and the drawer door body 402, and the drawer body 401 is also fixed to the bracket 204, thereby implementing mutual fixation of the drawer door body 402 and the drawer body 401.

The second engaging portion 20 is connected to the cabinet 500 and/or the lower rail 203.

Here, a fixed frame 205 is connected to one end of the second engaging portion 20, a cavity is formed between the second engaging portion 20 and the fixed frame 205, the upper rail 201, the middle rail 202, the lower rail 203 and the bracket 204 are located in the cavity, and the fixed frame 205 and the lower rail 203 are fixed to each other.

It should be noted that the positions of the first engaging portion 10 and the second engaging portion 20 are not limited to the above description, and may be determined according to actual conditions so long as it is ensured that the first engaging portion 10 and the second engaging portion 20 can engage with each other to open or close the drawer 400 relative to the cabinet 500.

In the present embodiment, one of the first engaging portion 10 and the second engaging portion 20 is a gear, and the other is a rack.

In the present embodiment, an example is taken in which the first engaging portion 10 is a gear 10 and the second engaging portion 20 is a rack 20, but the arrangement is not limited thereto.

Here, the gear 10 is an independent gear. In other embodiments, the gear 10 may be a gear set formed by a plurality of gears.

The rack 20 has a tooth surface 21 for the gear 10 to travel thereon. The rack 20 includes a main rack 22 and an extension rack 23.

With reference to FIG. 3 and FIG. 4, when the drawer 400 is in the closed state, the tooth surface 21 has a first travel length L1. With reference to FIG. 5 and FIG. 6, when the drawer 400 is in the opening process, the extension rack 23 moves onto a travel path of the gear 10 so that the tooth surface 21 has a second travel length L2. When the drawer 400 is in the closing process, the extension rack 23 returns, and the first travel length L1 is smaller than the second travel length L2.

Here, the “tooth surface 21” refers to a region where the gear 10 can roll, and the “travel path of the gear 10” refers to a region through which the gear 10 passes while the drawer 400 is pushed in or pulled out.

In addition, the extension rack 23 may be in a moving state during the entire opening process of the drawer 400, or the extension rack 23 may only start to move after the drawer 400 is opened a certain distance, or the drawer 400 is still in the opening process after completion of the movement of the extension rack 23, which will be specifically determined according to actual situations.

It can be seen that the length of the tooth surface 21 of the rack 20 of the present embodiment is variable, and the length of the tooth surface 21 becomes larger during the opening of the drawer 400, so that the pull-out distance of the drawer 400 becomes larger, which facilitates the user to have access to articles in the drawer 400 and improves the user experience. In addition, the length of tooth surface 21 only increases while the drawer 400 is opened. In the closed state, the length of tooth surface 21 is small. The presence of the extension rack 23 does not hinder the normal opening and closing process of the drawer 400.

It needs to be appreciated that since the slide rail assemblies 200 are further provided on the left and right sides of the drawer 400, the traveling process of the drawer 400 may be further controlled by the slide rail assemblies 200, and the gear 10 may be prevented from directly disengaging from the rack 20 while the drawer 400 is in the opening process.

In the present embodiment, two gears 10 are provided on the left and right sides of the drawer 400. The two gears 10 are connected by a link 30, and the two gears 10 move synchronously, thereby avoiding shaking or jamming during the opening and closing process of the drawer 400.

In addition, a support rod 50 is also connected between the two brackets 204. The support rod 50 is disposed adjacent the link 30. The support rod 50 is used to support the drawer body 401.

It can be seen that in the travelling process of the drawer 400 of the present embodiment, synchronization can be ensured, and it can also be ensured that the drawer 400 has a sufficiently large pull-out distance. Especially for a heavier drawer 400, the stability of the drawer 400 during the entire push-in and pull-out process can be guaranteed.

In the present embodiment, the engaging assembly 100 further includes a driving member 40, the extension rack 23 is movably connected to the main rack 22, and the driving member 40 is used to control the movement of the extension rack 23 relative to the main rack 22 to achieve changes in the length of the tooth surface 21.

It can be appreciated that the extension rack 23 is not necessarily movably connected to the main rack 22, and the extension rack 23 may also be movably connected to other regions, for example, the extension rack 23 is movably connected to the cabinet 500 so long as it can be ensured that the driving member 40 may act upon and move the extension rack 23 to achieve the changes of the length of the tooth surface 21.

The main rack 22 includes a first end portion 221 and a second end portion 222 which are arranged opposite to each other. A direction from the first end portion 221 to the second end portion 222 is the direction in which the drawer 400 is opened.

Here, the first end portion 221 and the second end portion 222 are defined as two opposite side portions of the main rack 22.

The main rack 22 has a main tooth surface 223, and the extension rack 23 has an extension tooth surface 231.

With reference to FIG. 3 and FIG. 4, when the drawer 400 is in a closed state, the tooth surface 21 has the first travel length L1.

With reference to FIG. 5 and FIG. 6, when the drawer 400 is in the opening process, the driving member 40 drives the extension rack 23 to move.

When the drawer 400 is in the open state, the driving member 40 drives the extension rack 23 to move onto the travel path of the gear 10, the extension rack 23 protrudes beyond the second end portion 222 in a direction away from the first end portion 221, and the extension tooth surface 231 is spliced with the main tooth surface 223 into a continuous tooth surface. At this time, plus the portion of the extension rack 23 protruding out of the second end portion 222, the tooth surface 21 has the second travel length L2, and the drawer 400 may be pulled out a longer distance.

Here, the “continuous tooth surface” means that the gear 10 can continuously travel on the tooth surface without interruption.

When the drawer 400 is in the closing process, the driving member 40 drives the extension rack 23 to move.

When the drawer 400 is in the closed state, the extension rack 23 returns so that the tooth surface 21 restores to the first travel length L1.

It may be appreciated that the “closed state” means that the drawer 400 is completely received in the cabinet 500, the “open state” means that the drawer 400 is fully opened, the “opening process” refers to a process in which the drawer 400 changes from the closed state to the open state, and the “closing process” refers to a process in which the drawer 400 changes from the open state to the closed state.

It should be appreciated that the operations of the engaging assembly 100 and the slide rail assembly 200 according to the present embodiment may also be implemented by electric control.

In the following, specific embodiment of the engaging assembly 100 according to the present implementation will be described in detail.

With reference to FIG. 7 through FIG. 12, they are schematic diagrams of the first embodiment of the engaging assembly 100.

Referring to FIG. 7 and FIG. 8, the engaging assembly 100 includes a gear 10 connected to a bracket 204 and a rack 20 connected to a cabinet 500 or a lower rail 203.

The rack 20 includes a main rack 22 and an extension rack 23.

The main rack 22 has a main tooth surface 223, and the extension rack 23 has an extension tooth surface 231.

The main rack 22 includes a first end portion 221 and a second end portion 222 which are arranged opposite to each other. A direction from the first end portion 221 to the second end portion 222 is the direction in which the drawer 400 is opened.

The extension rack 23 is pivotally connected to the second end portion 222 of the main rack 22.

Specifically, with reference to FIG. 9 through FIG. 11, one end of the extension rack 23 has a recessed portion 232, two openings 233 are provided on both sides of the recessed portion 232, the second end portion 222 of the main rack 22 is inserted into the recessed portion 232, and protrusions 2221 engaging with the openings 233 are disposed on both sides of the second end portion 222, so the extension rack 23 may rotate relative to the second end portion 222 of the main rack 22.

The second end portion 222 of the main rack 22 is provided with a limiting portion 2222, 2223.

Here, the limiting portion includes limiting teeth 2222 and a limiting surface 2223.

The limiting teeth 2222 are a toothed structure located at a front face of the second end portion 222. The limiting teeth 2222 may be a continuation of the main rack 22, that is, the tooth structure of the limiting teeth 2222 is consistent with the tooth structure of the main rack 22 at this time, but the arrangement is not limited thereto.

The limiting teeth 2222 and the main rack 22 may be an integrally formed structure, or may be assembled together after being separately formed.

Alternatively, the main rack 22 is formed by splicing two parts, and one part adjacent to the extension rack 23 is provided with the limiting teeth 2222.

The limiting teeth 2222 cooperate with the extension rack 23.

The limiting surface 2223 is located on the rotation path of the extension rack 23. The limiting surface 2223 is located in the region of the protrusion 2221 in the present implementation.

An adapting surface 234 that cooperates with the limiting surface 2223 is provided on the side of the extension rack 23.

A return torsion spring 24 is provided at a position where the extension rack 23 is pivotally connected with the main rack 22, and the return torsion spring 24 is sleeved around at least one protrusion 2221.

With reference to FIG. 12, the engaging assembly 100 further includes a driving member 40.

Here, the driving member 40 is an inclined surface located on the bracket 204. The driving member 40 may be directly formed by cutting and bending a portion of the bracket 204. However, the forming of the driving member 40 is not limited thereto.

The extension rack 23 has an adapting portion 235 that cooperates with the driving member 40. Here, the adapting portion 235 is a raised edge of the extension rack 23 extending toward a side away from the drawer 400.

Referring to FIG. 7, when the drawer 400 is in the closed state, the driving member 40 is far away from the extension rack 23, the return torsion spring 24 gives the extension rack 23 an acting force to drive the extension rack 23 to rotate towards the second end portion 222, the lower end of the extension rack 23 engages with the limiting teeth 2222, the adapting surface 234 of the extension rack 23 and the limiting surface 2223 interfere with each other, the extension rack 23 cannot continue to rotate towards the second end portion 222, and the extension rack 23 is in a stationary state relative to the main rack 22.

Referring to FIG. 12, when the drawer 400 is in the opening process, the driving member 40 gradually approaches and contacts the adapting portion 235, the driving member 40 acts on the adapting portion 235 to cause the extension rack 23 to rotate away from the second end portion 222, the extension rack 23 extends beyond the second end portion 222 in a direction away from the first end portion 221, and the extension tooth surface 231 is gradually spliced with the main tooth surface 223 into a continuous tooth surface.

When the drawer 400 is in the open state, the extension tooth surface 231 is in a horizontal state, and the gear 10 abuts against the end of the extension tooth surface 231 away from the second end portion 222 to prevent the extension rack 23 from rotating toward the second end portion 222.

When the drawer 400 is in the closing process, the driving member 40 gradually disengages from the adapting portion 235, and the return torsion spring 24 returns and drives the extension rack 23 to rotate toward the second end portion 222. When the extension rack 23 rotates and contacts the limiting portion (namely, when the lower end of the extension rack 23 engages with the limiting teeth 2222, and the adapting surface 234 of the extension rack 23 and the limiting surface 2223 interfere with each other), the extension rack 23 cannot continue to rotate towards the second end portion 222.

Here, when the drawer 400 is in the closed state, an angle between the extension rack 23 and the main rack 22 ranges from 30° to 120°. Preferably, the angle between the extension rack 23 and the main rack 22 is an acute angle, but not limited to thereto.

In addition, the end of the extension rack 23 far from the second end portion 222 may be a two-segment pivotally-connected structure. In this way, when the drawer 400 is in the closed state, the two-segment pivotally-connected structure can be doubled over to reduce the space occupied by the extension rack 23. In other words, at this time, the extension rack 23 with a sufficiently long unfolded length can also be accommodated in a limited space, thereby further increasing the pull-out distance of the drawer 400.

In the present embodiment, the gear 10 is disposed on the upper rail 201, the gear 10 enters and exits with the drawer 400, and the rack 20 is fixed on the cabinet 500 or the lower rail 203.

In other embodiments, with reference to FIG. 13, the positions of the gear 10 and the rack 20 are interchangeable.

Specifically, the gear 10′ is fixed at the front end of the cabinet 500, i.e., the gear 10′ is fixed at the opening of the cabinet 500, the rack 20′ is fixed at the bracket 204, the rack 20′ includes the main rack 22′ and the extension rack 23′ which are pivotally connected, the extension rack 23′ is located at the rear end of the main rack 22′, and a return torsion spring is disposed at a position where the extension rack 23′ is pivotally connected with the main rack 22′.

When the drawer 400 is in the closed state, the return torsion spring gives the extension rack 23′ an acting force to drive the extension rack 23′ to rotate towards the main rack 22′, and the extension rack 23′ and the main rack 22′ are in a doubled-over state and stationary relative to each other.

When the drawer 400 is in the opening process, the main rack 22′ first enables the gear 10′ to travel; when the gear 10′ reaches the boundary between the main rack 22′ and the extension rack 23′, the gear 10′ drives the extension rack 23′ to rotate away from the main rack 22′, the drawer 400 may be further pulled out, and the drawer 400 may be pulled out further.

When the drawer 400 is in the closing process, the extension rack 23′ first enables the gear 10′ to travel; when the gear 10′ reaches the boundary between the main rack 22′ and the extension rack 23′, the gear 10′ gradually disengages from the extension rack 23′, the extension rack 23′ gradually rotates toward the main rack 22′ under the action of the return torsion spring, and the extension rack 23′ returns.

It should be noted that this embodiment may also include a structure such as a driving member. Reference may be made to the depictions of the previous embodiment for other depictions of this embodiment, which will not be described in detail any more.

In addition, in this embodiment, the gear 10′ is not necessarily fixed at the front end of the cabinet 500′. For example, the gear 10′ may be movably disposed in the middle of the cabinet 500′, and so on.

With reference to FIG. 14 through FIG. 17, they show schematic diagrams of a second embodiment of an engaging component 100 a.

Here, for convenience of illustration, the same terms are used for structures having the same or similar functions.

The engaging assembly 100 a includes a gear 10 a connected to a bracket 204 a and a rack 20 a connected to the cabinet or a lower rail.

The rack 20 a includes a main rack 22 a and an extension rack 23 a.

The main rack 22 a has a main tooth surface 223 a, and the extension rack 23 a has an extension tooth surface 231 a.

The main rack 22 a includes a first end portion 221 a and a second end portion 222 a which are arranged opposite to each other. A direction from the first end portion 221 a to the second end portion 222 a is the direction in which the drawer 400 is opened.

A receiving space S1 is provided in a region of the main rack 22 a adjacent to the second end portion 222 a, and the extension rack 23 a is movably disposed in the receiving space S1.

Specifically, the receiving space S1 includes a bottom portion S11 far from the main tooth surface 223 a and a top portion S12 adjacent to the main tooth surface 223 a.

Here, the bottom portion S11 is a lower end region of the receiving space S1, the bottom portion S11 for example may be directly a portion of the cabinet 500, and the top portion S12 is an upper end opening of the receiving space S1.

The receiving space S1 has a side wall S13 connecting the bottom portion S11 with the top portion S12.

Here, an example is taken in which the receiving space S1 has two side walls S13 disposed opposite each other.

The side wall S13 is provided with at least one travel slot S131, and the extension rack 23 a is provided with a projection 232 a mating with the travel slot S131.

Here, an example is taken in which each side wall S13 is provided with two travel slots S131 distributed in parallel.

An angle in a direction away from the first end portion 221 a is provided between the travel slot S131 and the bottom portion S11, and the angle is an acute angle.

An elastic member 24 a is provided between the extension rack 23 a and the bottom portion S11.

Here, the elastic member 24 a is several springs evenly distributed.

The engaging assembly 100 a further includes a driving member 40 a.

Here, the driving member 40 a is a tab on a connecting sheet 403 a and has an inclined abutment surface, but is not limited thereto.

The extension rack 23 a has an adapting portion 235 a that cooperates with the driving member 40 a. Here, the adapting portion 235 a is a portion of the extension rack 23 a that the teeth project towards a region close to the bracket 204 a.

With reference to FIG. 14 and FIG. 15, when the drawer 400 is in the closed state, the driving member 40 a abuts against the adapting portion 235 a, the elastic member 24 a is compressed, the extension rack 23 a is located between the bottom portion S11 and the top portion S12, and the extension tooth surface 231 a is in a horizontal state.

Referring to FIG. 16 and FIG. 17, when the drawer 400 is in the opening process, the driving member 40 a gradually disengages from the adapting portion 235 a as the drawer 400 moves away from the first end portion 221 a, and then the elastic member 24 a returns to drive the extension rack 23 a to move towards the top portion S12 in the receiving space S1, and the extension tooth surface 231 a is gradually spliced with the main tooth surface 223 a into a continuous tooth surface.

Here, the extension tooth surface 231 a can be raised to be flush with the main tooth surface 223 a (i.e., the extension tooth surface 231 a and the main tooth surface 223 a are spliced into a continuous tooth surface) by controlling the elasticity of the elastic member 24 a, or, the rising height of the extension tooth surface 231 a can be controlled by providing a limiting member at the top portion S12.

In addition, the projection 232 a slides in the travel slot S131 to drive the extension rack 23 a to move close to the top portion S12. Since the travel slot S131 is an inclined travel slot, when the extension rack 23 a moves up close to the top portion S12, the extension rack 23 a also substantially moves away from the first end portion 221 a and protrudes beyond the second end portion 222 a.

When the drawer 400 is in the open state, the extension tooth surface 231 a is flush with the main tooth surface 223 a to form a continuous tooth surface.

When the drawer 400 is in the closing process, the driving member 40 a abuts against the adapting portion 235 a so that the extension rack 23 a moves closer to the bottom portion S11, the elastic member 24 a is compressed, and the extension rack 23 a returns.

In this embodiment, the main tooth surface 223 a includes a rear main tooth surface 2231 a located in an intermediate region between the top portion S12 and the first end portion 221 a, and a front main tooth surface 2232 a located at the top portion S12, and the rear main tooth surface 2231 a is continuous with the front main tooth surface 2232 a.

In this way, when the extension tooth surface 231 a rises to the top portion S12, the extension tooth surface 231 a is substantially located between two rows of front main tooth surfaces 2232 a, and the teeth of the extension tooth surface 231 a align with teeth of the front main tooth surface 2232 a.

The advantages of setting the front main tooth surface 2232 a are as follows: (1) when some errors occur with the alignment between the extension tooth surface 231 a and the front main tooth surface 2232 a, adjustment can be made through the front main tooth surface 2232 a; (2) when the extension tooth surface 231 a is not docked with the rear main tooth surface 2231 a (i.e., there is a gap between the extension tooth surface 231 a and the rear main tooth surface 2231 a), the front main tooth surface 2232 a may compensate the gap between the extension tooth surface 231 a and the rear main tooth surface 2231 a, so that the gear 10 a may travel continuously, to put it another way, the accuracy requirements for the extension tooth surface 231 a also reduce; (3) the tooth width formed by the extension tooth surface 231 a and the front main tooth surface 2232 a becomes larger, which may improve the stability in engaging with the gear 10 a.

The cooperation between the extension rack 23 a and the main rack 22 a may be in various forms, and a few examples are presented below for illustration.

With reference to FIG. 18 and FIG. 19, the travel slot S131′ is a vertical travel slot.

Referring to FIG. 18, when the drawer 400 is in the closed state, the extension rack 23 a′ is located between the bottom portion S11′ and the top portion S12′, and a distance through which one end of the extension rack 23 a′ protrudes beyond the second end portion 222 a′ of the main rack 22 a′ is a first distance.

Referring to FIG. 19, when the drawer 400 is in the opening process, the extension rack 23 a′ rises in the vertical direction due to the limitation of the travel slot S131′. When the extension rack 23 a′ rises to the top portion S12′, the extension rack surface 231 a′ is continuous with the rear main tooth surface 2231 a′, the distance through which the extension rack 23 a′ protrudes beyond the second end portion 222 a′ of the main rack 22 a′ is still the first distance.

With reference to FIG. 20 and FIG. 21, the travel slot S131″ is an inclined travel slot. When the drawer is in the closed state, the extension rack 23 a″ is located between the bottom portion S11″ and the top portion S12″, a distance through which one end of the extension rack 23 a″ protrudes beyond the second end portion 222 a″ of the main rack 22 a″ is a second distance, and the other end of the extension rack 23 a″ protrudes beyond the rear main tooth surface 2231 a″ (i.e., there is an overlapping region between the extension rack 23 a″ and the rear main tooth surface 2231 a″ at this time).

Referring to FIG. 20, when the drawer 400 is in the opening process, the extension rack 23 a″ rises obliquely due to the limitation of the travel slot S131″; when the extension rack 23 a″ rises to the top portion S12″, the extension rack 23 a″ is continuous with the rear main tooth surface 2231 a″, and the distance of the extension rack 23 a″ protruding beyond the second end portion 222 a″ of the main rack 22 a″ is greater than the second distance.

With reference to FIG. 22 through FIG. 29, they show schematic diagrams of a third embodiment of an engaging assembly 100 b.

Here, for convenience of illustration, the same terms are used for structures having the same or similar functions.

With reference to FIG. 22 through FIG. 24, the engaging assembly 100 b includes a gear 10 b connected to a bracket 204 b and a rack 20 b connected to a cabinet or a lower rail.

The rack 20 b includes a main rack 22 b and an extension rack 23 b.

The main rack 22 b has a main tooth surface 223 b, and the extension rack 23 b has an extension tooth surface 231 b.

The main rack 22 b includes a first end portion 221 b and a second end portion 222 b which are arranged opposite to each other. A direction from the first end portion 221 b to the second end portion 222 b is the direction in which the drawer is opened.

A receiving space S2 is provided in a region of the main rack 22 b close to the second end portion 222 b, the extension rack 23 b is movably disposed in the receiving space S2, and the extension rack 23 b and the receiving space S2 cooperate with each other so that the extension tooth surface 231 b and the main tooth surface 223 b are always at the same height.

Here, the receiving cavity S2 is a cavity formed between the main rack 22 b and the bracket 204 a.

Specifically, with reference to FIG. 25 through FIG. 27, the engaging assembly 100 b further includes a driving member 40 b which is connected to the extension rack 23 b.

Here, the driving member 40 b includes a link 41 b, a slider 42 b and a driving block 43 b.

The link 41 b is a rigid link.

The link 41 b is used to connect the extension rack 23 b with the slider 42 b, the link 41 b is fixedly connected with the extension rack 23 b, and the link 41 b is rotatably connected with the slider 42 b, i.e., the slider 42 b is rotatable relative to the link 41 b.

The slider 42 b is provided with a notch 421 b that fits the driving block 43 b.

The notch 421 b is surrounded by a first bump 4211 b and a second bump 4212 b, the first bump 4211 b is disposed adjacent to the second end portion 222 b, and the second bump 4212 b is disposed adjacent to the first end portion 221 b.

The driving block 43 b is a rigid member in the middle of the bracket 204 b.

The driving member 40 b further includes a return spring 44 b connected to the slider 42 b.

A fixing seat S22 for accommodating the return spring 44 b is disposed in the receiving space S2.

The fixing seat S22 and the cabinet are fixed to each other.

One end of the return spring 44 b is fixedly connected to the fixing seat S22, and the other end is connected to the slider 42 b.

An accommodating slot S21 for accommodating the driving member 40 b and the extension rack 23 b is disposed in the receiving space S2.

The accommodating slot S21 and the cabinet are fixed to each other, and one end of the accommodating slot S21 is connected to the fixing seat S22.

The accommodating slot S21 includes two opposite side walls S211, each side wall S211 has a first slot S2111, a second slot S2112 and a third slot S2113, and the second slot S2112 and the third slot S2113 have equal lengths.

The first slot S2111 includes a first section S2111′ adjacent to the first end portion 221 b and a second section S2111″ adjacent to the second end portion 222 b. The second section S2111″ is away from the main tooth surface 223 b relative to the first section S2111′.

That is, the first slot S2111 is an “L”-shaped slot, and the second section S2111″ extends downward relative to the first slot S2111.

The first slot S2111 is substantially parallel to the second slot S2112, and the third slot S2113 is located below the first slot S2111.

Here, two connected first posts 422 b are disposed at an end of the slider 42 b adjacent to the notch 421 b, a second post 423 b is disposed on a lateral side of the extension rack 23 b, and a third post 424 b is disposed at the connection of the slider 42 b and the link 41 b.

The first slot S2112 engages with two first posts 422 b to restrict the moving direction of the slider 42 b, the second slot S2112 engages with the second post 423 b to restrict the moving direction of the extension rack 23 b, and the third slot S2113 engages with the third post 424 b to restrict the moving direction of the third post 424 b.

Here, the connection of the extension rack 23 b and the link 41 b is defined as a connection point, and the connection line between the connection point, the second post 423 b and the third post 424 b forms an obtuse triangle, which is stable in structure and may ensure the stability of the movement of the extension rack 23 b.

Referring to FIG. 22 through FIG. 27, when the drawer 400 is in the closed state, the driving block 43 b is located in the notch 421 b and engages with the slider 42 b.

Referring to FIG. 28, when the drawer 400 is in the opening process, the driving block 43 b drives the extension rack 23 b to move away from the first end portion 221 b via the slider 42 b and the link 41 b, and the return spring 44 b is stretched.

Specifically, with reference to FIG. 29, the driving block 43 b drives the slider 42 b to travel from the first section S2111′ to the second section S2111″. Since the second section S2111″ is lower than the first section S2111′, the slider 42 b rotates relative to the link 41 b in a direction away from the first end portion 221 b, the first bump 4211 b of the notch 421 b inclines downwards to cause the driving block 43 b to disengage from the notch 421 b, and the slider 42 b is located in the second section S2111″. At this time, the extension rack 23 b has moved in a direction away from the first end portion 221 b and protruded beyond the second end portion 222 b, and the extension tooth surface 231 b and the main tooth surface 223 b are spliced into a continuous tooth surface.

That is, since the extension tooth surface 231 b and the main tooth surface 223 b are always at the same height, only the horizontal movement of the extension rack 23 b can cause the extension rack 23 b to protrude beyond the second end portion 222 b.

When the drawer 400 is in the open state, the extension tooth surface 231 b is flush with the main tooth surface 223 b to form a continuous tooth surface.

When the drawer 400 is in the closing process, the driving block 43 b drives the extension rack 23 b to move toward the first end portion 221 b via the slider 42 b and the link 41 b.

Specifically, at this time, the slider 42 b is located in the second section S2111″, and the first bump 4211 b is in a downwardly inclined state, the driving block 43 b enters the notch 421 b across the first bump 4211 b (namely, an inclined side bump), the return spring 44 b returns and drives the slider 42 b to rotate toward the first end portion 221 b, the slider 42 b returns so that the driving block 43 b and the notch 421 b engage with each other, the return spring 44 b continues to act on the slider 42 b, the first bump 4211 b acts on the driving block 43 b, then the driving block 43 b drives the slider 42 b to travel from the second section S2111″ to the first section S2111′, and then the return spring 44 b continues to drive, via the slider 42 b, the driving block 43 b, the link 41 b and the extension rack 23 b to move together toward the first end portion 221 b and return.

It should be appreciated that in the present implementation, the cooperation of the return spring 44 b, the slider 42 b and the driving block 43 b is used to implement the return of the engaging assembly 100 b. This return structure may also be incorporated into the first and second embodiments described above, which will not detailed any more here.

In the present embodiment, the main tooth surface 223 b includes a rear main tooth surface 2231 b adjacent to the first end portion 221 b and a front main tooth surface 2232 b adjacent to the second end portion 222 b, and the rear main tooth surface 2231 b is continuous with the front main tooth surface 2232 b.

When the drawer 400 is in the closed state, the extension tooth surface 231 b is disposed adjacent to the front main tooth surface 2232 b. Preferably, at this time, the extension tooth surface 23 b, the front main tooth surface 2232 b and the rear main tooth surface 2231 b are tightly spliced together.

When the drawer 400 is in the opening process, the extension tooth surface 231 b moves in a direction away from the front main tooth surface 2232 b so that the extension tooth surface 231 b protrudes beyond the second end portion 222 b.

When the drawer 400 is in the closing process, the extension tooth surface 231 b moves toward the front main tooth surface 2232 b and returns.

The advantages of setting the front main tooth surface 2232 b are as follows: (1) when some errors occur with the alignment between the extension tooth surface 231 a and the front main tooth surface 2232 b, adjustment can be made through the front main tooth surface 2232 a; (2) when the extension tooth surface 231 b is not docked with the rear main tooth surface 2231 b (i.e., there is a gap between the extension tooth surface 231 b and the rear main tooth surface 2231 b), the front main tooth surface 2232 a may compensate the gap between the extension tooth surface 231 b and the rear main tooth surface 2231 b, so that the gear 10 b may travel continuously, to put it another way, the accuracy requirements for the extension tooth surface 231 b also reduce; (3) the tooth width formed by the extension tooth surface 231 b and the front main tooth surface 2232 b becomes larger, which may improve the stability in engaging with the gear 10 b.

In addition, the total width formed by the extension tooth surface 231 b and the front main tooth surface 2232 b in the present embodiment is preferably larger than the width of the rear main tooth surface 2231 b. On the one hand, the stability in engaging with the gear 10 b may be improved, and on the other hand, the width of the extension tooth surface 231 b may be appropriately increased to improve the stability of the horizontal movement of the extension rack 23 b.

It should be understood that although the description is described according to the embodiments, not every embodiment only includes one independent technical solution, that such a description manner is only for the sake of clarity, that those skilled in the art should take the description as an integral part, and that the technical solutions in the embodiments may be suitably combined to form other embodiments understandable by those skilled in the art.

The detailed descriptions set forth above are merely specific illustrations of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications that do not depart from the art spirit of the present invention should fall within the scope of protection of the present invention. 

What is claimed is:
 1. An engaging assembly for assisting in opening or closing a drawer, wherein the engaging assembly comprises a gear configured for engaging with the drawer and a rack configured for engaging with a cabinet, the rack has a tooth surface enabling the gear to travel along the tooth surface, and the rack comprises a main rack and an extension rack; when the drawer is in a closed state, the tooth surface has a first travel length; when the drawer is in an opening process, the extension rack moves onto a travel path of the gear so that the tooth surface has a second travel length; when the drawer is in a closing process, the extension rack returns, and the first travel length is shorter than the second travel length, the main rack comprises a first end portion and a second end portion which are arranged opposite to each other, a direction from the first end portion to the second end portion is a direction in which the drawer is opened, and the extension rack is pivotally connected to the second end portion, and a return torsion spring is provided at a connection of the extension rack and the main rack; when the drawer is in the opening process, the extension rack rotates relative to the second end portion and protrudes beyond the second end portion in a direction away from the first end portion by overcoming a restoring force of the spring, the engaging assembly further comprises a driving member, and the extension rack has an adapting portion that is able to engage with the driving member; when the drawer is in the opening process, the driving member acts on the adapting portion by overcoming the restoring force of the spring to cause the extension rack to rotate in a direction away from the first end portion; when the drawer is in the closing process, the driving member disengages from the adapting portion to release the spring and cause the extension rack to rotate in a direction close to the first end portion; when the drawer is in the closed state, the extension rack protrudes upward from the main rack due to the spring, and an acute angle is formed between the extension rack and the main rack.
 2. The engaging assembly according to claim 1, wherein the main rack has a main tooth surface, and the extension rack has an extension tooth surface; when the drawer is in an open state, the extension tooth surface and the main tooth surface are spliced into a continuous tooth surface.
 3. The engaging assembly according to claim 1, wherein when the drawer is in an opening process, the driving member drives the extension rack to move onto the travel path of the gear; when the drawer is in the closing process, the driving member allows the extension rack to return.
 4. The engaging assembly according to claim 1, wherein the main rack has a main tooth surface, and the extension rack has an extension tooth surface; when the drawer is in the opening process, the extension rack rotates relative to the second end portion so that the extension tooth surface and the main tooth surface are spliced into a continuous tooth surface.
 5. The engaging assembly according to claim 1, wherein a limiting portion is disposed at the second end portion of the main rack; when the extension rack rotates in a direction adjacent to the second end portion and contacts the limiting portion, the limiting portion restricts the extension rack from continuing to rotate in the direction adjacent to the second end portion.
 6. A drawer, configured to be received in a cabinet and movable out from and into the cabinet, wherein the drawer comprises a slide rail mechanism, the slide rail mechanism comprises an engaging assembly, the slide rail assembly has an upper rail, a middle rail and a lower rail that are slidingly fitted to each other, the lower rail is configured to be connected to the cabinet, the middle rail is movably connected to the upper rail and the lower rail, the upper rail is connected to the drawer, a gear of the engaging assembly is connected to the upper rail, and a rack of the engaging assembly is connected to at least one of the cabinet and the lower rail; wherein the rack has a tooth surface enabling the gear to travel along the tooth surface, and the rack comprises a main rack and an extension rack; when the drawer is in a closed state, the tooth surface has a first travel length; when the drawer is in an opening process, the extension rack moves onto a travel path of the gear so that the tooth surface has a second travel length; when the drawer is in a closing process, the extension rack returns, and the first travel length is shorter than the second travel length, the main rack comprises a first end portion and a second end portion which are arranged opposite to each other, a direction from the first end portion to the second end portion is a direction in which the drawer is opened, and the extension rack is pivotally connected to the second end portion, and a return torsion spring is provided at a connection of the extension rack and the main rack; when the drawer is in the opening process, the extension rack rotates relative to the second end portion and protrudes beyond the second end portion in a direction away from the first end portion by overcoming a restoring force of the spring, the engaging assembly further comprises a driving member, and the extension rack has an adapting portion that is able to engage with the driving member; when the drawer is in the opening process, the driving member acts on the adapting portion by overcoming the restoring force of the spring to cause the extension rack to rotate in a direction away from the first end portion; when the drawer is in the closing process, the driving member disengages from the adapting portion to release the spring and cause the extension rack to rotate in a direction close to the first end portion; when the drawer is in the closed state, the extension rack protrudes upward from the main rack due to the spring, and an acute angle is formed between the extension rack and the main rack.
 7. A refrigerator, wherein the refrigerator comprises the drawer according to claim 6 and a cabinet to receive the drawer therein.
 8. The drawer according to claim 6, wherein the slide rail mechanism comprises two slide rail assemblies and two engaging assemblies located on opposite sides of the drawer, and the two gears are connected by a link. 